1// Copyright 2016 The Xorm Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package builder
6
7import (
8	"fmt"
9)
10
11// Select creates a select Builder
12func Select(cols ...string) *Builder {
13	builder := &Builder{cond: NewCond()}
14	return builder.Select(cols...)
15}
16
17func (b *Builder) selectWriteTo(w Writer) error {
18	if len(b.from) <= 0 && !b.isNested {
19		return ErrNoTableName
20	}
21
22	// perform limit before writing to writer when b.dialect between ORACLE and MSSQL
23	// this avoid a duplicate writing problem in simple limit query
24	if b.limitation != nil && (b.dialect == ORACLE || b.dialect == MSSQL) {
25		return b.limitWriteTo(w)
26	}
27
28	if _, err := fmt.Fprint(w, "SELECT "); err != nil {
29		return err
30	}
31	if len(b.selects) > 0 {
32		for i, s := range b.selects {
33			if _, err := fmt.Fprint(w, s); err != nil {
34				return err
35			}
36			if i != len(b.selects)-1 {
37				if _, err := fmt.Fprint(w, ","); err != nil {
38					return err
39				}
40			}
41		}
42	} else {
43		if _, err := fmt.Fprint(w, "*"); err != nil {
44			return err
45		}
46	}
47
48	if b.subQuery == nil {
49		if _, err := fmt.Fprint(w, " FROM ", b.from); err != nil {
50			return err
51		}
52	} else {
53		if b.cond.IsValid() && len(b.from) <= 0 {
54			return ErrUnnamedDerivedTable
55		}
56		if b.subQuery.dialect != "" && b.dialect != b.subQuery.dialect {
57			return ErrInconsistentDialect
58		}
59
60		// dialect of sub-query will inherit from the main one (if not set up)
61		if b.dialect != "" && b.subQuery.dialect == "" {
62			b.subQuery.dialect = b.dialect
63		}
64
65		switch b.subQuery.optype {
66		case selectType, setOpType:
67			fmt.Fprint(w, " FROM (")
68			if err := b.subQuery.WriteTo(w); err != nil {
69				return err
70			}
71
72			if len(b.from) == 0 {
73				fmt.Fprintf(w, ")")
74			} else {
75				fmt.Fprintf(w, ") %v", b.from)
76			}
77		default:
78			return ErrUnexpectedSubQuery
79		}
80	}
81
82	for _, v := range b.joins {
83		b, ok := v.joinTable.(*Builder)
84		if ok {
85			if _, err := fmt.Fprintf(w, " %s JOIN (", v.joinType); err != nil {
86				return err
87			}
88			if err := b.WriteTo(w); err != nil {
89				return err
90			}
91			if _, err := fmt.Fprintf(w, ") ON "); err != nil {
92				return err
93			}
94		} else {
95			if _, err := fmt.Fprintf(w, " %s JOIN %s ON ", v.joinType, v.joinTable); err != nil {
96				return err
97			}
98		}
99
100		if err := v.joinCond.WriteTo(w); err != nil {
101			return err
102		}
103	}
104
105	if b.cond.IsValid() {
106		if _, err := fmt.Fprint(w, " WHERE "); err != nil {
107			return err
108		}
109
110		if err := b.cond.WriteTo(w); err != nil {
111			return err
112		}
113	}
114
115	if len(b.groupBy) > 0 {
116		if _, err := fmt.Fprint(w, " GROUP BY ", b.groupBy); err != nil {
117			return err
118		}
119	}
120
121	if len(b.having) > 0 {
122		if _, err := fmt.Fprint(w, " HAVING ", b.having); err != nil {
123			return err
124		}
125	}
126
127	if len(b.orderBy) > 0 {
128		if _, err := fmt.Fprint(w, " ORDER BY ", b.orderBy); err != nil {
129			return err
130		}
131	}
132
133	if b.limitation != nil {
134		if err := b.limitWriteTo(w); err != nil {
135			return err
136		}
137	}
138
139	return nil
140}
141
142// OrderBy orderBy SQL
143func (b *Builder) OrderBy(orderBy string) *Builder {
144	b.orderBy = orderBy
145	return b
146}
147
148// GroupBy groupby SQL
149func (b *Builder) GroupBy(groupby string) *Builder {
150	b.groupBy = groupby
151	return b
152}
153
154// Having having SQL
155func (b *Builder) Having(having string) *Builder {
156	b.having = having
157	return b
158}
159