// like expression expects the target expression and pattern to be a string, if it's not, we add a cast function.
func (v *typeInferrer) handleLikeExpr(x *ast.PatternLikeExpr) {
x.SetType(types.NewFieldType(mysql.TypeLonglong))
x.Type.Charset = charset.CharsetBin
x.Type.Collate = charset.CollationBin
x.Expr = v.addCastToString(x.Expr)
x.Pattern = v.addCastToString(x.Pattern)
}
func (e *Evaluator) patternLike(p *ast.PatternLikeExpr) bool {
expr := p.Expr.GetDatum()
if expr.IsNull() {
p.SetNull()
return true
}
sexpr, err := expr.ToString()
if err != nil {
e.err = errors.Trace(err)
return false
}
// We need to compile pattern if it has not been compiled or it is not static.
var needCompile = len(p.PatChars) == 0 || !ast.IsConstant(p.Pattern)
if needCompile {
pattern := p.Pattern.GetDatum()
if pattern.IsNull() {
p.SetNull()
return true
}
spattern, err := pattern.ToString()
if err != nil {
e.err = errors.Trace(err)
return false
}
p.PatChars, p.PatTypes = compilePattern(spattern, p.Escape)
}
match := doMatch(sexpr, p.PatChars, p.PatTypes)
if p.Not {
match = !match
}
p.SetInt64(boolToInt64(match))
return true
}